Question

点P在曲线y=x³-3x+7上移动,过P点的切线的倾斜角的取值范围是(    )

A.[0,π]                             B.[0,)∪[,π)

C.[0,)∪(,π)              D.[0,]∪[,π)

Answer 1

解析：y′=3x²-≥-,即tanα≥-.

∴α∈[0,)∪[,π).

答案：B